Detergent composition of improved foam performance



2,863,836 DETERGENT COMPOSITION OF IMPROVED FOAM PERFORMANCE Richard D.Stayner, Berkeley, Calif., assignor to California Research Corporation,San Francisco, Calif., a

corporation of Delaware No Drawing. Application September 23, 1955Serial No. 536,265 3 Claims. (Cl. 252-152) This invention relates toanionic sulfated synthetic detergent compositions having improvedproperties.

Although the exact relationship between foaming and detergency ofanionic sulfated synthetic detergents is not known, the formulatorspreparing detergent compositions intended for use in agitator-typewashing machines strive to impart the best foam performance to thesecompositions, that is to aqueous dilute solutions thereof. Thesedesirable foam characteristics are: (1) good quality, which means a foamtexture of uniformly small-sized bubbles having a white, lather-likeconsistency; (2) stability in the presence of soil; (3) persistenceunder agitation in the bowl of a washing machine, particularly when thesame detergent solution is employed repeatedly (that is, in amultiplicity of washing cycles); and (4) high mechanical stabilityresulting in a slow decay rate.

To impart simultaneously good quality, stability and persistence to thefoam of a conventional dilute aqueous washing solution of an anionicdetergent formulation is definitely not a simple task, and itsrealization, without detracting at the same time from the detergent orcleansing property of the formulation, would promise a substantialexpansion of the popular demand for anionic sulfated synthetic detergentformulations.

I have found that the foam performance of a large group of organicsulfate detergents, namely, of those which contain in their molecularstructure a straight saturated C C hydrocarbon chain, can besurprisingly and significantly enhanced by adding to these sulfatedetergents a mixture or blend of a particular fatty acid amide and aparticular kind of a p-acyl phenoxy compound in certain critical weightratios, namely from 3 to 0.3 parts of the p-acyl phenoxy compound to 1part of the fatty acid amide, and preferably from 2:1 to 1:2.

The effective fatty acid amide component of the blend to be added to theorganic sulfate detergent for the purpose of improving its foamperformance in agitated aqueous solutions thereof is a primary amide ofpalmitic and/ or myristic acid (palmitamide and/ or myn'stamide).

The other component of the blend is a p-acyl phenoxy compound of thegeneral formula:

in which R is a straight C C saturated hydrocarbon chain and A is aradical from the group consisting of hydroxy, oxyethanol andoxethoxyethanol radicals. In other words, this component may be astraight-chain C C saturated p-acyl phenol, or a monoethylene glycol ora diethylene glycol ether of such a phenol. e

The organic sulfated detergents, whose aqueous solutions exhibitimproved foam performance on addition thereto of the aforementionedblend of the fatty acid amide and the p-acyl phenoxy compound, are thosewhich contain in their hydrophobic portion a straight Cpl-C1 icegenation techniques. Since the detergent alcohol sulfates of this kindordinarily produce an inadequate volume of foam or suds in agitateddilute aqueous solutions, in order to enhance the foam volume they arecombined with the well-known water-soluble detergent C -Cmonoalkylbenzene sulfonates, as exemplified by C -C polypropylenebenzene sulfonates, preferably in proportions from about 50% to as highas about 85% of the combined weight of the organic sulfate and sulfonatedetergents. Furthermore, the compositions improved in accordance withthe invention may contain conventional watersoluble inorganic saltdetergent builders, such as sodium sulfate, sodium tripolyphosphate,tetrasodium pyrophosphate, sodium silicate, borax, sodium carbonate,etc. The total amount of these builders-may range from 40% to 90% of thecombined weight of organic sulfate and sulfonate detergents in theformulation, without adversely affecting the desirable action of thefoam-improving blend saturated hydrocarbon chain which can beinterrupted by groups such as -O, C(O)O, -C(O)NH etc., and particularlyWater-soluble organic straight-chain C C alcohol sulfates, preferablyderived from materials such as tallow by conventional hydrolysis andhydro and without detracting from the detergent property of the finalformulation. Additionally, conventional additives, such as extenders (e.g., carboxymethyl cellulose), optical bleach, emollients, perfume, dyes,anti-caking agents, etc., may be added to the detergent formulations inamounts which, as a rule, do not exceed all in all 5% by weight.

The aforementioned foam-improving blend is particu larly effective whenemployed in the detergent formulations in amounts ranging from about 5to about based on the weight of the detergent organic sulfate component.

The improved detergent compositions of the present invention can beformulated by employing any suitable known technique of the art.Detergent organic sulfates, and in particular straight-chain C14-C13alkyl (alcohol) sulfates derived from tallow by hydrolysis and hydrogenation procedures, may be combined with detergent alkyl benzenesulfonates, inorganic salt builders and other desired conventionaladditives in the proportions indicated hereinbefore and with thefoam-improving blend in accordance with the invention. Preferably, theseveral ingredients are combined to form a solution or a slurry,whereupon the resulting mixture is dried to give a particleform productcharacterized by a substantially uniform distribution of all of theingredients within each individual particle.

Often it may be preferred to prepare first the alkyl benzene sulfonicacid by sulfonating a suitable alkyl benzene stock with an excess ofconcentrated sulfuric acid or oleum and then to add to the sulfonationreaction mixture the sulfatable component, e. g., molten or flaked C -Caliphatic alcohols derived from hydrogenated tallow fatty acids, ormolten or flaked C C alkylolamides of 0 -0 straight-chain saturatedfatty acids. By employing an appropriate quantity of the sulfonatingagent, the desired weight ratio of detergent organic sulfate to alkylbenzene sulfonate is achieved in the final neutralized sulfate-sulfonateproduct slurry. Thereafter, the foam-improving agent prepared as a blendaccording to the invention, detergent builders and other additives whichmay be required, are introduced into the slurry, and this latter isdried to the solid particle form, or processed to yield a paste, ordiluted to form a liquid concentrate.

A typical detergent formulation, from 20 to 22% by weight of whichconsisted of detergent straight-chain C C alkyl sulfates, alkyl benzenesulfonates and the foam-improving agent of the invention was tested in aconventional agitator-type domestic washing machine.

The alkyl sulfate component of this formulation con' sisted of sodium C-C alkyl sulfates prepared by neutralizing sulfated alcohols derivedfrom hydrogenated tallow fatty acids, the larger proportion (60 to 70%by weight) being sodium C alkyl sulfates. The alkyl benzene sulfonatecomponent consisted of sodium C -C polypropylene benzene sulfonatesproduced in accord- .ance with the teaching of U. S. Patent 2,477,383 toA. H. Lewis. The weight ratio of the alkyl sulfate component to thealkyl benzene sulfonate component in this formulation was about 1:1. Thefoam-improving agent in all test runs was present in an amount equal toabout 2% by weight of the total formulation. The formulation wasfurthermore built by employing 30% of sodium tripolyphosphate, 20% oftetrasodium pyrophosphate, 5% of liquid commercial N" grade sodiumsilicate, the balance to make up 100% by weight being essentially soliumsulfate.

Dilute solutions of 0.3% concentration of this formulation in soft water(50 p. p. m. of calciummagnesium hardness calculated as calciumcarbonate and magnesium carbonate in the weight ratio .of 2:1) at atemperature of 120 F. were employed in the tests. The bowl of themachine, containing the test solution in an amount corresponding to theration specified therefor by its manufacturer, received a charge ofcotton towels (6 pounds) soiled with a specified amount of lard oil. Thelid of the bowl was closed and the machine was run the first cycle often minutes. Upon stopping the machine, the foam height in inches andthe quality of the suds were noted. More lard oil in the same amount asin the first cycle was added to the towels, and the ten-minute operatingcycle was repeated six times. At the end of each cycle, the foam heightand the quality of the suds were observed and the same amount of lardoil added. In the sixth and seventh cycle, however, lard oil was addedin the amount which was double of the amount originally applied in cycle1.

Table I.Cmparis0n of the effect of different foaml'mprow'ng agents onfoam performance P-aeyl Phenoxyethanol l Blend (50/50) Foam AdditiveFoam Foam Height Quality Height Quality 111 in Inches Inches 3.5 White,Stablev 2 White, Stable Lather-like.

0. 5 1. 5 Still white,

stable, creamy, soaplike.

1 Aeyl group derived from coconut oil fatty acids. 2 Blend of p-aeylphenoxycthanol and palmitamide.

When a monoethylene glycol ether of a p-acyl phenol (the acyl groupbeing derived from coconut oil fatty acids) was the sole foam-improvingadditive, the foam height was adequate at first (Nos. 1 to 4 cycles),but the suds lacked the desired lather-like quality. Furthermore, oncontinuing the multiple cycle operation, the suds decayed sooner, sothat at the end of the seventh cycle, less than. 0.5 inches of gray,irregular, lacy suds could be observed on the surface of the liquid inthe bowl. In contrast to the above, employment of a 50/ 50 blend ofpalmitamide and monoethylene glycol ether of p-acyl phenol (the acylgroup being derived from coconut oil fatty acids) resulted in anadequate head of foam which retained its creamy, soap-like, whitetexture despite the multiple cycle operation and even at the end of theseventh cycle displayed an uninterrupted, fairly high (1 /2 inches) bodyof suds above the surface of the liquid in the bowl. The presence of aconventional amount of a hypochlorite bleach (0.005 to 0.03%), addedeither at the beginning or during the agitation of the solution, doesnot affect the stability of the foam.

A blend of palmitamide and p-acyl phenol (the acyl group being derivedfrom coconut oil fatty acids) is equally effective as a foam-improvingagent, provided hypochlorite bleaches are not employed. Addition of Ithese bleaches to the solutions prior to the addition of the detergentis found to impair the foam stability.

When the test solution is prepared by using hard water (300 p. p. m.calculated as calcium carbonate and magnesium carbonate in a weightratio of 2:1), the foam height and the quality of the suds produced bythe detergent composition containing the blend of the primary amide andthe p-acyl phenoxy compound are superior to those obtained by using theindividual components of the blend as the foam-improving agent.

In order to bring out the specificity 0f the fatty acid amides, presentas one of the components in the foamimproving agent of this invention, acomparative test series was carried out employing difi'erent fatty acidamides in the same detergent formulation containing a combination byweight) of organic sulfate and sulfonate detergents in a weight ratio of1:1 as the surface-active matcrial. The foam-improving additives in theamount of 2% by weight of the total solids in the formulation wereeither the long-chain saturated primary fatty acid amides alone orblends of these amides with a monoethylene glycol ether of p-acyl phenol(the acyl group being derived from coconut oil fatty acids). Builderswere present in the same amounts as in the previously described testseries. The test solution was prepared by dissolving the detergentformulation to 0.15% concentration in soft water p. p. m. ofcalcium-magnesium hardness in a weight ratio of 2:1). The bowl of thewashing machine containing this solution at a temperature of about F.received a charge (6 pounds) of cotton towels soiled with a specifiedamount of lard oil. The contents of the Table II.Effect of the presenceof diflerent amides in the foam-improving agent P-aeyl Phenoxy- FoamTest. Amide Percent; ethanol Height Foam Quality No. by Wt. in Perin cent by inches 2 2.8 White, creamy, very stiff, dry. 1 1 3. 4 White,creamy, moderately v stiti, wet. Palmitamide. 2 3.1 Brightly white, dry,crerhny,

very stiti. do 1 1 3.1 White, creamy, moderatelv stiti, wot.Stearam1de.. 2 r. 1.6 White, dry, chalky, very still. 3, 1 do 1 1 2.5White, wetter than in No. 5, moderately stiff. 7...--- None 3.5 Grey,definitely lat-y texture,

low hulk viscosity. 8 2 White, lacy, lacking in latherllrzc quality.

bowl were agitated in a conventional manner, their average foam heightin inches above the liquid level was observed after 2, 5, l0, l5 and 20minutes of operation.

The results shown in Table 11 indicate that the best suds are obtainedby employing the blend of palmitamide and the glycol ether of p-acylphenol (run No. 4). The foam height lies in the satisfactory range from2 /2 to 4 inches, while the quality of the foam is unquestionablyexcellent: it is white, creamy, soap-like and wet, although less stiffthan in run No. 3 where palmitamide is the sole foam-improving additive.In this latter instance, although a moderately high head of foam wasobtained on the surface of the wash solution, the bulk viscosity was toohigh, so that the suds were too stiff and rather chalky in appearance.Such suds are diflicult to eliminate after the washing cycle andinterfere with proper rinsing.

Myristamide added alone (run No. l), secures a foam which is lessdense-bodied (has lower bulk density) than with palmitamide alone, butis still more stiff and drier than when myristamide is added in a blendwith the monoethylene glycol ether of p-acyl phenol (p-acylphenoxyethanol), in which case it contributes to the latherlike qualityof foam, almost as good as that secured with the palmitamide blend (runNo. 2).

Stearamide employed alone is obviously unsatisfactory; the foam heightis low and the foam is dry, stiff and chalky (run No. 5). However,blended with the glycol ether of p-acyl phenol in a 50/50 weight ratio,stearamide gives a higher level of foam which has a wetter character(run No. 6).

Neither lauramide nor arachidamide (alone or in a blend with anacylphenoxyethanol) are satisfactory. The first amide fails tocontribute to an improved bulk viscosity of the foam and, therefore,cannot form densebodied, soaplather-like suds; the second causesformation of suds which are altogether. too stiff and chalky and are ofan inadequate volume.

Alkylolamides, e. g., stearic ethanolamide and palmitic ethanolamide,reported elsewhere in the art as foam-improving additives, are inferiorto palmitamide, whether alone or blended with the glycol ethers ofp-acyl phenols. The bubbles of the resulting foam are not creamy likesoap suds.

The aforegiven illustrative data clearly bring forth the advantages ofintroducing the foam-improving blend of the invention into the detergentformulations containing organic sulfated detergents in which thehydrophobic portion is characterized by the presence of a straightC14-C13 saturated hydrocarbon chain. These advantages are greater soiltolerance and higher mechanical stability and persistence underagitation in the presence of soil, being more effective inmultiple-cycle operation.

At this point I wish to reiterate that the aforegiven description andexamples are offered merely to illustrate the operativeness of theinvention, and that the foamimproving blends of palmitamide and/ormyristamide with lower molecular weight glycol ethers of p-acyl phenols,or with the corresponding p-acyl phenols, are effective in improvingfoam characteristics of other similar organic sulfated detergents; forinstance, sulfated alkylolamides of straight-chain C C saturated fattyacids, sulfated monoglycerides of straight-chain C -C saturated fattyacids and of many other organic detergent sulfates, in which thehydrophobic portion contains a straight C -C saturated hydrocarbonchain.

I claim:

1. A detergent composition of improved foam performance consistingessentially of, by weight, 15 to parts of a saturated normal C -C alkylsulfate detergent, 50 to parts of a (l -C monoalkyl benzene sulfonatedetergent, and, as foam-improving material, about /2 to 2 parts ofsaturated normal c -c fatty acid amide per one part of apara-acylphenoxy compound of the formula wherein R is a straight C -Csaturated hydrocarbon chain and A is a radical from the group consistingof hydroxy, oxyethanol and oxyethoxy-ethanol radicals, saidfoam-improving material being present in an amount from about 5% toabout 75% based on the sulfate detergent.

2. A detergent composition according to claim 1 wherein the monoalkylbenzene sulfonate detergent is a (Z -C polypropylene benzene sulfonatedetergent, the paraacylphenoxy compound is a straight-chain C -Cparaacylphenoxy ethanol and the saturated fatty acid amide ispalmitamide.

3. A built detergent composition consisting essentially of, by weight,10 to 40 percent of the composition as defined in claim 1, and 60 topercent of water-soluble inorganic salt builders.

References Cited in the file of this patent UNITED STATES PATENTS2,383,738 Richardson Aug. 28, 1945 2,477,383 Lewis July 26, 19492,519,062 Miskel Aug. 15, 1950 2,768,956 Scott Oct. 30, 1956 2,772,239Lewis Nov. 27, 1956 FOREIGN PATENTS 157,394 Australia Aug. 23, 1951

1. A DETERGENT COMPOSITION OF IMPROVED FOAM PERFORMANCE CONSISTING ESSENTIALLY OF, BY WEIGHT, 15 TO 50 PARTS A SATURATED NORMAL C14-C18 ALKYL SULFATE DETERGENT, 50 TO 85 PARTS OF A C9-C18 ALKYL SULFATE DESULFONATE DETERGENT, AND, AS FOAM-IMPROVING MATERIAL, ABOUT 1/2 TI 2 PARTS OF SATURATED NORMAL C14-C16 FATTY ACID AMIDE PER ONE PART OF A PARA-ACYLPHENOXY COMPOUND OF THE FORMULA
 3. A BUILT DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF, BY WEIGHT, 10 TO 40 PERCENT OF THE COMPOSITION AS DEFINED IN CLAIM 1, AND 60 TO 90 PERCENT OF WATER-SOLUBLE INORGANIC SALT BUILDERS. 